Dynamic Stall Analysis in Light of Recent Numerical and Experimental Results

Abstract

An earlier developed engineering analysis of dynamic stall is reviewed in light of recent numerical and experimental results. It is found that the concept of equivalence between boundary-layer improvement due to piich-rate-induced effects and increasing Reynolds number is supported by the available numerical and experimental results. The existence of the postulated plunging-induced improvement of the boundary layer and associated delay of stall, the controversial leading-edge jet'* effect, is indicated by oscillatory stall data for different oscillation centers and by the measured negative aerodynamic damping for plunging oscillations in the stall region. More work is needed before the dynamic stall characteristics can be predicted for high frequencies. Until then, the present technique offers a reliable means for prediction of low-frequency (d)<0.5) dynamic stall characteristics from static experimental data.